If an electron falling from an excited state releases 4.1 x 10-19 J of energy, what is the
frequency of the light emited? answer choices>
O 6.18 x 10 (14)
O 6.18 x 10 (-14)
O 2.72 x 10 (52)
0 2.72 x 10 (-52)

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

The chemical formula for emerald is be3al2(sio3)6.an emerald can be decided as

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.